Before-mentioned valves are used in particular as pressure control valves for the control in gears in automatic gears. Known valves have, as a rule, several screens which are closed or released by sealing bodies. A solenoid acts for control purposes in a suitable manner on these sealing bodies. An important property of the known pressure controllers here is the pressure control characteristic line, that means the connection between the coil electricity running through the solenoid, and the controlled starting pressure. Another important characteristic of the known pressure control valves is the flow through the pressure control valve.
It is known that the flowing-through between the inlet and the outlet decreases with the falling operation temperature which is not desired. It has to be taken into consideration here that in the intended use the pressure control valves have to be used in a temperature range from −30° C. to +80° C., and the flowing-through should be constant, if possible, over the entire operation temperature interval, however, at least as high as possible.
However, with the known pressure control valves according to the state of the art it has been found that the flowing-through at −10° C. decreases to about 40% of the flow existing at a middle operation temperature of 60° C.